LXX Ezekiel 32:27
26 Meshech and Tubal were delivered up there, and all their strength all around its grave, all his wounded, all the uncircumcised wounded by the sword, who have given their terror over life. 27 And they slept with the giants, who had fallen from eternity, who descended into Hades with weapons of war, and placed their swords under their heads, and their lawless acts came upon their bones, because they terrified everyone in their life. 28 And you will sleep in the middle of the uncircumcised with those wounded by the sword.
2 Peter 2:4
3 And in their greed they will exploit you with deceptive words. Their condemnation pronounced long ago is not sitting idly by; their destruction is not asleep. 4 For if God did not spare the angels who sinned, but threw them into Tartarus16 and locked them up in chains in utter darkness, to be kept until the judgment, 5 and if he did not spare the ancient world, but did protect Noah, a herald of righteousness, along with seven others, when God brought a flood on an ungodly world,
Notes and References
"... The verbs “to cast into Tartarus,” and were almost always used with reference to the early Greek theogonic myths, in which the ancient giants, the Cyclopes and Titans, were imprisoned in Tartarus, the lowest part of the underworld, by Uranos, Kronos and Zeus. They are not used in the Greek version of 1 Enoch; though τάρταρος (“Tartarus”) is used of the place of divine punishment in 1 Enoch 20:2, as elsewhere in Jewish Greek literature (LXX Job 40:20; 41:24; Proverbs 30:16; Sibylline Oracles 4:186; Philo, Life of Moses 2.433). But Hellenistic Jews were aware that the Greek myth of the Titans had some similarity to the fall of the Watchers (though Philo, Gig. 58, rejects any comparison). Sometimes the Watchers’ sons, the giants (the Nephilim), were compared with the Titans (Josephus, Antiquities 1.73; compare LXX Ezekiel 32:27; Sirach 16:7) but in Judith 16:6 (and also the Christian passage Sibylline Oracles 2:231) the Watchers themselves seem to be called τιτᾶνες (“Titans”). Thus in using a term reminiscent of the Greek myth of the Titans the author of 2 Peter follows Hellenistic Jewish practice ..."
Bauckham, Richard Word Biblical Commentary: Jude-2 Peter (pp. 249-250) Zondervan, 1983